<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <!-- https://blog.csdn.net/xw1193195009/article/details/124100993 -->
   <style type="text/css">
       .div0 {
            width: 500px;
            background: green;
            display: flex;
       }
       .div0 div{
           width: 100px;
           height: 100px;
           background-color: yellow;
       }
   </style>
</head>
<body>
    <div class="div0">
        <div>1</div>
        <div>2</div>
        <div>3</div>
        <div>4</div>
       
    </div>
    
    
</body>
</html>